Fryers are extensively used in the food industry to cook various comestibles. A common type of fryer includes a relatively deep container with the comestible to be cooked immersed in cooking oil in the container. In commercial operations, the comestibles are cooked in batches with the cooking oil used repeatedly. The cooking oil, after sufficient use, becomes contaminated with food particles or other impurities. Charred food particles produce an odor which adversely affects the taste of foods cooked therein.
In prior art systems, cooking oil is cleaned by pumping it through a filter assembly often containing filter paper or other disposable filter element. A filter powder is normally applied to the filter element by dispersal in the cooking oil. This filter powder serves to precipitate particulates and to control odors. Filter powders commonly consist of diatomaceous earth, pearlite or magnesium silica.
U.S. Pat. No. 4,805,525 to the present inventor discloses a cooking oil filtering apparatus for removal of particulates from cooking oil. Cooking oil is drawn through wire mesh screens supported outside a filter insert by applying a suction interior of the wire mesh screens and the filter insert. A re-issue application Ser. No. 07/813,870 is pending in relation to the subject patent. The subject apparatus eliminates the need for filter paper.
This applicant's co-pending U.S. application Ser. No. 07/947,479 discloses a continuous filtering fryer, the continuous filtering fryer comprising a filtering element including wire mesh screens, a filter insert, an outlet line from the filter insert to a suction pump, and an inlet line. The pump draws cooking oil through the wire mesh screens and returns the cooking oil to the container.
The prior art discloses methods for treating cooking oils. Such methods include Liebermann U.S. Pat. No. 5,068,115 which discloses an immersible packet containing citrus peels and Roy International Application PCT/US93/01737 which discloses extension of edible oil lifetime using activated carbons. The prior art does not disclose a device having the characteristics of providing filtering of cooking oil and concurrently treating the cooking oil by exposing it to materials to improve the physical or chemical properties of the cooking oil as disclosed in the present invention.
It is an object of the present invention to provide a filtering device that provides effective filtration and treatment of the liquid being filtered.
It is another object of the present invention to provide a filtering device that effectively filters cooking oil during cooking operation and concurrently treats the cooking oil to maintain or improve characteristics of the cooking oil.
It is another object of the present invention to provide a permanent filter element having replaceable components to provide for treatment of liquid to achieve desired characteristics of the liquid.
It is another object of the present invention to provide a filtering device for concurrent filtering and chemical treatment of cooking oil.
It is another object of the present invention to provide a filtering device that provides effective continuous filtration.
These and other objects of the present invention will become apparent from a reading of the attached specification and appended claims.